/*
 * Copyright 2020 Adobe. All rights reserved.
 * This file is licensed to you under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. You may obtain a copy
 * of the License at http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
 * OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

import {Color, ColorSliderProps} from '@react-types/color';
import {normalizeColor, parseColor} from './Color';
import {SliderState, useSliderState} from '@react-stately/slider';
import {useControlledState} from '@react-stately/utils';
import {useMemo, useState} from 'react';

export interface ColorSliderState extends SliderState {
  /** The current color value represented by the color slider. */
  readonly value: Color,
  /** Sets the current color value. If a string is passed, it will be parsed to a Color. */
  setValue(value: string | Color): void,
  /** Returns the color that should be displayed in the slider instead of `value` or the optional parameter. */
  getDisplayColor(): Color,
  /** Whether the color slider is currently being dragged. */
  readonly isDragging: boolean
}


export interface ColorSliderStateOptions extends ColorSliderProps {
  /** The locale to use for formatting the color channel value. */
  locale: string
}

/**
 * Provides state management for a color slider component.
 * Color sliders allow users to adjust an individual channel of a color value.
 */
export function useColorSliderState(props: ColorSliderStateOptions): ColorSliderState {
  let {channel, colorSpace, value, defaultValue, onChange, locale, ...otherProps} = props;
  if (value == null && defaultValue == null) {
    throw new Error('useColorSliderState requires a value or defaultValue');
  }

  if (value) {
    value = normalizeColor(value);
  }
  if (defaultValue) {
    defaultValue = normalizeColor(defaultValue);
  }
  // safe to cast value and defaultValue to Color, one of them will always be defined because if neither are, we throw an error
  let [colorValue, setColor] = useControlledState<Color>(value as Color, defaultValue as Color, onChange);
  let color = useMemo(() => colorSpace && colorValue ? colorValue.toFormat(colorSpace) : colorValue, [colorValue, colorSpace]);
  let [initialValue] = useState(colorValue);
  let defaultColorValue = (defaultValue as Color) ?? initialValue;
  let defaultColor = useMemo(() => colorSpace && defaultColorValue ? defaultColorValue.toFormat(colorSpace) : defaultColorValue, [defaultColorValue, colorSpace]);
  let sliderState = useSliderState({
    ...color.getChannelRange(channel),
    ...otherProps,
    // Unused except in getThumbValueLabel, which is overridden below. null to localize the TypeScript error for ignoring.
    // @ts-ignore
    numberFormatter: null,
    value: color.getChannelValue(channel),
    defaultValue: defaultColor.getChannelValue(channel),
    onChange(v) {
      setColor(color.withChannelValue(channel, v));
    },
    onChangeEnd(v) {
      // onChange will have already been called with the right value, this is just to trigger onChangeEnd
      if (props.onChangeEnd) {
        props.onChangeEnd(color.withChannelValue(channel, v));
      }
    }
  });

  let {step, pageSize} = color.getChannelRange(channel);
  return {
    ...sliderState,
    value: color,
    setValue(value) {
      setColor(normalizeColor(value));
    },
    getDisplayColor() {
      switch (channel) {
        case 'hue':
          return parseColor(`hsl(${color.getChannelValue('hue')}, 100%, 50%)`);
        case 'lightness':
        case 'brightness':
        case 'saturation':
        case 'red':
        case 'green':
        case 'blue':
          return color.withChannelValue('alpha', 1);
        case 'alpha': {
          return color;
        }
        default:
          throw new Error('Unknown color channel: ' + channel);
      }
    },
    getThumbValueLabel() {
      return color.formatChannelValue(channel, locale);
    },
    step,
    pageSize,
    isDragging: sliderState.isThumbDragging(0)
  };
}